Dicloxacillin: a higher risk than cloxacillin for infusion phlebitis.

Ever since dicloxacillin and cloxacillin were introduced in the 1960s, it has been known that they are associated with a high incidence of infusion phlebitis. Some in vitro studies and clinical experience have indicated that dicloxacillin is the more vessel-irritating of the 2 drugs. In this prospective observational study on 39 patients with 111 peripheral venous catheters (PVCs), the incidence of infusion phlebitis was compared between these 2 drugs. The incidence of phlebitis was 38% with dicloxacillin and 21% with cloxacillin; which, compared by logistic regression with other risk factors as covariates, was significant [odds ratio 5.06, 95% confidence interval (95% CI) 1.45-17.60]. Since the duration of catheterization is also an important risk factor, Cox regression was performed, and the difference between the 2 drugs was still significant (proportional hazard rate 3.48, 95%, CI 1.64-7.38). The only other significant risk factor found in the study was the insertion site; the risk was higher in PVCs inserted in the forearm/antecubital fossa than in the hand/wrist. The infusion time and dilution of the infusate were not significant risk factors.